<!--
  ~ Copyright (C) 2010 Brockmann Consult GmbH (info@brockmann-consult.de)
  ~
  ~ This program is free software; you can redistribute it and/or modify it
  ~ under the terms of the GNU General Public License as published by the Free
  ~ Software Foundation; either version 3 of the License, or (at your option)
  ~ any later version.
  ~ This program is distributed in the hope that it will be useful, but WITHOUT
  ~ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  ~ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  ~ more details.
  ~
  ~ You should have received a copy of the GNU General Public License along
  ~ with this program; if not, see http://www.gnu.org/licenses/
  -->

<html>
<head>
    <title>Sentinel Toolbox Help - Export GCP</title>
    <link rel="stylesheet" href="../style.css">
</head>

<body>
<table class="header">
    <tr class="header">
        <td class="header">&nbsp;
            Export GCP</td>
        
    <td class="header" align="right"><a href="../general/overview/SnapOverview.html"><img src="../images/snap_header.jpg" border=0></a></td>
    </tr>
</table>

<h3>Export Envi GCP File</h3>

<p>This command allows to store the geo-coding information of the selected product
    as ENVI GCP (Ground Control Points) file. </p>

<h3>ENVI GCP File Format</h3>

<p><i>Text taken from the <b>
            <object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">     
                <param name="content" value="http://www.harrisgeospatial.com/portals/0/pdfs/enviex/ENVI_EX_User_Guide.pdf">
                <param name="text" value="<html><u>ENVI User's Guide</u></html>">
            </object></b></i>.</p>
<br>

<p>The ENVI Ground Control Point (GCP) files are ASCII files that contain the pixel
    coordinates of tie points selected from a base and warp image using ENVI's
    registration utilities. They are assigned the file extension <code>.pts</code> by default and begin
    with the keywords "ENVI Registration GCP File." For image-to-image registration,
    pixel coordinates are listed in the order Base image X, Y, Warp Image X, Y. An
    example of a typical image-to-image .pts file is shown here:</p>


<pre>
    ENVI Registration GCP File
    921.00000 2538.0000 2098.0000 111.00000
    1381.0000 2291.0000 2145.0000 85.000000
    1669.0000 2116.0000 2174.0000 66.000000
    119.00000 3032.0000 2017.0000 164.00000
    1286.0000 3820.0000 2140.0000 240.00000
    1294.0000 1754.0000 2132.0000 28.000000
    1783.0000 1814.0000 2184.0000 34.000000
    715.00000 4504.0000 2083.0000 312.00000
    351.00000 1708.0000 2039.0000 27.000000
    207.00000 2357.0000 2025.0000 98.000000
</pre>

<p>For image-to-map registration, coordinates are listed as map X, map Y, image X,
    image Y. An example of a typical image-to-map .pts file is shown here:</p>

<pre>
    ENVI Registration GCP File
    359459.810 4143531.300 288.000 496.000
    367681.530 4141772.000 232.000 23.000
    366343.470 4138660.500 458.000 35.000
    362337.840 4145969.500 71.000 388.000
    361339.910 4138479.300 569.000 301.000
    354457.530 4140550.300 591.000 714.000
    354352.590 4145685.000 261.000 819.000
    359918.310 4142412.000 351.000 448.000
    364900.910 4141752.300 290.000 172.000
</pre>
<hr>
</body>
</html>